We report briefly the fossilized chemosynthetic molluscan assemblages found along the coastal area of Tabango and Villaba municipalities, northwestern Leyte, Philippines. This is the first discovery of fossil cold-seep assemblages in Southeast Asia. The geology of the study area is tentatively divided here into four formations ; namely, Formations A (locs. 11-13, upper Miocene), B (loc. 10, upper Miocene to lower Pliocene), C (locs. 1-9, lower Pliocene), and D (loc. 2, upper Pliocene or lower Pleistocene) from older to younger, based on lithology and calcareous nannofossil biostratigraphy. Among these formations, Formations A, B, and C yield fossil cold-seep assemblages. The assemblages show considerable variations in their modes of fossil occurrence. At location 4, several huge indurated carbonate blocks (ca. 5 meters in maximum diameter ; δ¹³C =-42.03‰ and δ¹⁸O = 0.91%o vs. PDB), lags of weathered sediments, contain beautifully preserved, large vesicomyid, lucinid, thyasirid, and mytilid bivalves. Inarticulated valves of vesicomyds and lucinids are dispersed within a slump bed at location 5. Densely packed, articulated lucinids are in massive authigenic carbonates at locations 2 and 7. Large articulated solemyid valves, attaining 20 cm in maximum shell length, show sporadic occurrences in massive siltstone (loc. 10). A swarm of articulate and inarticulate lucinid valves are found together with conglomerates of calcareous gravels within asphalt sands (loc. 12). The importance of this discovery is : (1) it provides the first record from the barren area of fossil cold-seep assemblages in Southeast Asia; (2) beautifully preserved fossil material that might contribute to the systematics of fossil cold-seep bivalves ; and, (3) greater number of variations of modes of fossil occurrence in a limited area and horizon than anywhere else so far documented.